The invention relates to a sealing arrangement for valves, gates or flap valves, specifically for the use in the ultra high vacuum technique, having a sealing surface formed at an outer flange and a sealing surface cooperating with same and located at the outer circumference of an axially movable closure unit (valve disk), which includes at least one biassing member becoming active by the axial movement for an increasing of the outer circumference for a pressing of the sealing surfaces onto each other.
In a known sealing arrangement of this kind the two-part closure unit consists of a planar disk having an elastically deformable annular bead at the outer circumference and a ring which is movable in an axial direction, having a smaller diameter and arranged coaxially to the disk and located in the plane of the bead-like rim. A cup spring supported at the outside on the ring and at the inside at the bead-like rim acts as a coupling member between the two parts and can be pressed by means of an axially movable ring from a relaxed position into a completely planar position, in which in order to produce a pressing-on force onto the sealing surfaces it has its largest diameter and attains practically a dead-center position. A safe functioning for an obtaining of an absolutely sealed closure at changing temperatures is not safely ensured by this arrangement.
Therefore, the present invention is directed to providing a sealing arrangement of this kind in which the biassing element producing the pressing-on force is not a coupling member between two parts which are movable relative to each other and which up to reaching the dead-center position continuously move away from each other under the influence of the spring force and need the continuous action of a pressing-on force.
In order to achieve this object the inventive sealing arrangement comprises a cap shaped outer part formed with a planar base, which is elastically deformable and includes at its outer circumference a sealing surface for a cooperation with a further sealing surface of an outer flange, an inner part concentric to the outer part and having a smaller diameter, and biassing members arranged along an annulus which provide the action of a cup spring, or instead thereof also only a cup spring is present. The biassing members, which can be held and supported at the outer part in an annular tee-slot shaped recess are arranged inclined obliquely radially towards the inside against the base of the outer part, while the pressure for the actuating is directed towards the outer part base, with the effect that the elastically deformable outer part base attains an inwardly pressed position without the bracing elements reaching a dead-center position. The elastic deformability of the outer part base is enhanced also specifically in that a radially inwardly extending groove is formed in the integral closure part between the inner part and the base.
An embodiment of the invention will hereinafter be explained more in detail with reference to the drawings.